Contact reflex manifold imaging process

ABSTRACT

A contact reflex manifold imaging process is provided wherein a manifold set comprising an electrically photosensitive imaging layer which is structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which the layer is sensitive releasably resides on a transparent donor sheet and is in contact with a transparent receiver sheet. A master to be copied is placed in contact with one side of the manifold set and is exposed to a pattern of electromagnetic radiation to which the imaging layer is sensitive by passing the electromagnetic radiation through the manifold set while the imaging layer is subjected to an electric field. Upon separation of the manifold set while under a field and after the exposure, the imaging layer fractures in imagewise configuration whereby a positive image is observed on one of the donor and receiver sheets and a negative image is observed on the other sheet.

United States Patent l1 l Krohn et al.

l l CONTACT REFLEX MANIFOLD IMAGING PROCESS [75] Inventors: Ivar T. Krohn; Geoffrey A. Page;

Vesvolod Tulagin, all of Rochester- NYv [73] Assignee: Xerox Corporation, Stamford.

Conn,

{22] Filed: Jan. 2, 1970 [21] Appl No: 86

[52} US. Cl a 96/l M [51] Int. Cl. t. G03G 17/00 [58} Field of Search 96H 1.3. 1.4, l M;

ll7/l7.5, 37 LX l 56] References Cited UNITED STATES PATENTS 3.955.938 lU/l960 Steinhilper 0. 96/14 2 965i48l lZ/l960 Gundlach it 3102.026 8/l963 Metcalfe et a] a 3.271.]45 9/1966 Robinson 3512.968 5/1970 Tulagin 3545.969 12/l97t) Herrick et al 4. 96/L4 X 1 Nov. 11, 1975 Primary E.t'mniiic'l'charles E, Van Horn [57] ABSTRACT A contact reflex manifold imaging process is provided wherein a manifold set comprising an electrically photosensitive imaging layer which is structurally fractur able in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which the layer is sensitive releasably resides on a transparent donor sheet and is in contact with a transparent receiver sheet. A master to be copied is placed in contact with one side of the manifold set and is exposed to a pattern of electromagnetic radiation to which the imaging layer is sensitive by passing the electromagnetic radiation through the manifold set while the imaging layer is subjected to an electric field. Upon separation of the manifold set while under a field and after the exposure. the imaging layer fractures in imagewise configuration whereby a positive image is observed on one of the donor and receiver sheets and a negative image is observed on the other sheetv 33 Claims, 4 Drawing Figures ommqmaramsxawmme i EQQQQQEI US. Patent Nov. 11, 1975 3,918,967

alwmammmsmiwwmmwmmmi a'ygm' mi IIIIII'IIIII'IIIIIII FIG: 4 INVENTORS IVAR T. KROHN GEOFFREY A. mes BY VSEVOLOD TULAGIN ATTORNEY CONTACT REFLEX MANIFOLD IMAGING PROCESS BACKGROUND OF THE INVENTION This invention relates to the manifold imaging process and more particularly to the use of contact reflex imaging in conjunction with the manifold imaging process.

Photosensitive image reproducing systems commonly use expensive and bulky optical lens exposure systems for focusing a light pattern on the photosensitive surface. In making a size-to-size reproduction of a transparency. the optical lens is avoided by placing the transparency directly in contact with the photosensitive surface and shining light through the transparency. Unfortunately, the direct light system will not work when the original is opaque.

Previously, it has not been possible to utilize the manifold imaging process with reflex-type exposure. The conventional manifold process is fully described in cpending application Ser. No. 708,380 filed Feb. 26, 1968. It was generally believed that the manifold imaging layers would not respond to imagewise transfer from a donor sheet to a receiver sheet upon illumination of sufficient intensity to penetrate the imaging layer irrespective of any additional radiation reflected back to the imaging layer from any image surface as in a reflux system. However, a reflex system has many advantages over other reproduction methods. Two of the main reasons are the savings possible in terms of money and space. In a contact reflex system, a lens system is excluded. Lenses of good optical quality are expensive. Their elimination is an appreciable savings. Further, placing a copy in contact with the manifold set rather than at a distance determined by the focal length of a lens system, makes possible substantial reductions in space requirements with consequent increased flexibility of design.

There has now been discovered a novel imaging process which now makes possible reflex copying in a manifold imaging system.

SUMMARY OF THE INVENTION Therefore. it is an object of this invention to define a method of reflex exposure in a manifold imaging system.

A further object of this invention is to define means for imaging an original positioned in closely spaced relationship to the manifold set.

Another object of this invention is to provide a manifold imaging process which avoids the necessity of employing optical focusing of the image pattern by means of a lens system.

Another object of this invention is to provide a manifold imaging process which produces right-reading images on opaque substrates.

These and other objects of this invention will become apparent upon reading the following description of the invention.

There has now been discovered a contact reflex manifold imaging process utilizing a manifold set comprising an electrically photosensitive imaging layer releasably residing upon a transparent donor sheet and which is in contact with a transparent receiver sheet. The manifold set is placed in contact with a master to be duplicated and while the imaging layer is subjected to an electric field the master is flood illuminated by passing light through the manifold set. Light reflected back from the master in non-image areas exposes the imaging layer on the side opposite the light source. Surprisingly enough, light is transmitted through the imaging layer, although solid coverage of the donor sheet is usually the case, to provide exposure of the master and reflection therefrom. As will be more fully explained below, the imaging layer is thus exposed from both directions in those areas overlying non-image areas of the master while those areas of the imaging layer overlying the image portions of the master are illuminated from one direction only. Upon separation of the manifold set while under a field, the imaging layer fractures and an imagewise pattern is found on each of the donor and receiver sheets, one of which will be a negative image and the other of which will be a positive of the original master.

In accordance with the process of this invention, right-reading positive-from-positive images can be provided. For example, a transparent donor or receiver can be employed in the process of this invention and then rendered opaque as described below.

Another means for obtaining right-reading positive copies on opaque substrates in accordance with this invention is to image expose a master resting against the receiver side of a manifold set employing a transparent donor and receiver sheet and then altering the electric field prior to separating the manifold set in accordance with the procedure of copending application Ser. No. 609,058 filed Jan. 13, I967 now abandoned which is incorporated herein by reference. A positive wrong reading image resides on the donor sheet upon separation of the manifold set. An opaque substrate, preferably wetted with an activator for the imaging layer, is substituted for the receiver sheet and the manifold set is reformed. An electric field is reapplied across the manifold set with the polarity adjusted to duplicate that employed during imagewise exposure. While under this electric field, the manifold set is again separated and a positive, right-reading image is residing on the opaque substrate. In some instances the above procedure is performed, but the master is positioned adjacent the donor sheet. A positive right-reading image is then obtained on the transparent donor sheet if the electric field is not reversed subsequent to exposure but prior to the separation of the set. To obtain a right-reading opaque copy, the field is reversed after exposure but prior to separation of the manifold set. After separation an opaque substrate, preferably wetted with an activator, fluid, is substituted for the donor sheet and the manifold set reformed. An electric field is reestablished across the set having the same polarity as employed during the imagewise exposure step. Upon separation of the set, a positive. right-reading image appears on the opaque substrate.

The process of this invention is clearly useful for the production of transparency images. Such images are normally employed to provide enlarged images by means of an overhead projector.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages of this improved method of imaging will become apparent upon consideration of the detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a side sectional view of a manifold sandwich for use in this invention.

FIG. 2 is a side sectional view diagramatically illustrating the exposure step of the process of this invention.

FIG. 3 is a side sectional view diagramatically illustrating the separation of the manifold set in the process of this invention.

FIG. 4 is a side sectional view diagramatically illustrating the preferred method of illuminating the maste while subjecting the imaging layer to an electric field.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIG. 1, imaging layer 2 comprising electrically photosensitive material 3 dispersed in binder 4 is releasably residing on the surface of donor sheet 5. Receiver sheet 6 is in contact with imaging layer 2 to complete the manifold set.

The imaging layer 2 serves as the photoresponsive element of the system s well as the colorant for the final image produced. Other colorants such as dyes and pigments may be added to the imaging layer so as to intensify or modify the color of the final image produced when color is important. Preferably, the imaging layer is selected so as to have a high level of response while at the same time being intensly colored so that a high contrast image can be formed. The imaging layer may be homogeneous comprising. for example, a solid solution of two or more pigments. The imaging layer may also be heterogeneous comprising, for example. pigment particles dispersed in a binder as illustrated in FIG. 1. The thickness of the imaging layer. whether homogeneous or heterogeneous, ranges from about 0.2 micron to about l microns, generally about 0.5 micron to about microns and preferably about 2 microns. The ratio of photose nsitive pigment to binder, by weight, in the heterogeneous system may range from about ID to I to about 1 to 1() respectively, but it has generally been found that ratios in the range of from about I to 4 to about 2 to 1 respectively produce the best results and. accordingly, this constitutes a preferred range.

The binder material in the heterogeneous imaging layer or the material used in conjunction with the electrically photosensitive materials in the homogeneous layer, where applicable, may comprise any suitable cohesively weak insulating material or materials which can be rendered cohesively weak. Typical materials include: microcrystalline waxes such as: Sunoco I290, Sunoco 5825. Sunoco 985. all available from Sun Oil Co.; Paraflint RG, available from the Moore and Munger Company; paraffin waxes such as: Sunoco 5512, Sunoco 3425, available from Sun Oil Co.; Sohio Parowax, available from Standard Oil of Ohio; waxes made from hydrogenated oils such as Capitol City I380 wax. available from Capitol City Products Co., Columbus. Ohio; Caster Wax L-2790. available from Baker Caster Oil Co.; Vitikote L-304, available from Duro Commodities; polyethylenes such as: Eastman Epolene NJ I. Eastman Epolene C -l2, available from Eastman Chemical Products. Co.; Polyethylene DYJT, Polyethylene DYLT. Polyethylene DYDT. all available from Union Carbide Corp.; Marlex TR 822. Marlex 1478. available from Phillips Petroleum Co.: Epolene C-l3. Epolene C- l 0, available from Eastman Chemical Products, Co; Polyethylene AC8, Polyethylene ACol'l. Polyethylene AC324, available from Allied Chemicals; modified styrenes such as: Piccotex 75. Piccotex 100. Piccotex I20. available from Pennsylvania Industrial Chemical; Vinylacetate-ethylene copolymers such as:

Elvax Resin Zlt). Elvax Resin 310. Elvax Resin 420, available from E. I. duPont de Nemours & Co. Inc.. Vistanex L-Sll. available from Enjay Chemical Co; vinyl chloride-vinyl acetate copolymers such as: Vinylite UYLF. available from Union Carbide Corp.; styrene-vinyl toluene copolymers; polypropylenes; and mixtures thereof. The use of an insulating binder is preferred because it allows the use of a larger range of electrical field strength.

Normally the imaging layer of this invention is coated onto a sheet referred to above as the donor sheet or substrate. For convenience. the combination of imaging layer and donor sheet is referred to as the donor. When self-supporting imaging layers are employed, a support or substrate is employed where the layer is rendered structurally fracturable. The combination of structurally weak imaging layer and supporting substrate is also referred to as a donor. When employing a binder, the electrically photosensitive material can be mixed in the binder material by conventional means for blending solids as by ball millings. After blending the ingredients of the imaging layer. the desired amount is coated on a substrate.

The imaging layer may be supplied in any color desired, either by taking advantage of the natural color of the photosensitive material or binder materials in the imaging layer or by the use of additional dyes and pigments therein whether photoresponsive or not and, of course, various combinations of these photosensitive and non-photosensitive colorants may be used in the imaging layer so as to produce the desired color.

Donor sheet 5 and receiver sheet 6 may comprise any suitable electrically insulating or electrically conducting material. Electrically insulating materials are preferred since they allow the use of high strength polymeric material. In addition, the donor sheet and the receiver sheet are at least partially transparent to the electromagnetic radiation to which the imaging layer is sensitive because in accordance with the process of this invention the electromagnetic radiation passes through the manifold set to the master to be copied and is reflected back through one of the donor or receiver sheets to the imaging layer snadwiched therebetween. Typical insulating mate rials include polyethylene, polypropylene, polyethylene terephthalate, cellulose acetate, polyesters, paper. plastic coated paper, such as polyethylene coated paper, vinyl chloride-vinylidene chloride coplymers and mixtures thereof. Mylar (a polyester formed by the cndensation reaction between ethyelen glycol and terephthalic acid available from E. I. duPont de Nemours & Co., Inc.) is preferred because of its durability and excellent insulative properties. Not only does the use of this type of high strength polymer provide a strong substrate for the positive and negative images formed on the donor substrate and receiver sheet but, in addition, it provides an electrical barrier between the electrodes and the imaging layer which tends to inhibit electrical breakdown of the system while subjecting the manifold sandwich to an electric field. The donor sheet and receiver sheet may each be selected from different materials. Thus. a manifold sandwich can be prepared by employing an insulating donor sheet while a conductive material is employed as a receiver sheet.

In addition. the donor and receiver sheets may comprise materials which are transparent but which can be treated to modify their visible appearance after the imaging procedure is completed. For example. transparent sheets can be coated with a mixture of silver behenate, behanic acid and protocatechuic acid in accordance with the teaching of U.S. Pat. No. 2,910,377 which is incorporated herein by reference. Upon heating the coated sheet, a reaction occurs in the coating to provide a visible change in the color of the sheet.

Another method of modifying the visible appearance of the transparent donor or receiver sheet is to coat at least one surface with a penetrating liquid which upon heating causes a microscopic pattern of differential cohesion at the surface of the sheet. Upon heating the surface becomes covered with microscopic somewhat irregularly shaped hemispherical bumps or projections which effectively diffuse the light. Various materials and method to accomplish the above are found in U.S. Pat. No. 3,1 l 1,584 which is incorporated herein by refcrence.

Alternatively, normally opaque or translucent materials can be employed in the process of this invention by being transparentized at the time the imaging layer is applied. In some instances the activator employed in the imaging process can also transparentize one or both of the donor and receiver sheets. For instance, mineral oil can be employed as an activator and as a transparentizer for bond paper donors and receivers. After the production of the image, the oil is removed returning the paper to its original capcity. Various other materials useful as activators also affect paper so as to temporarily transparentize it for use in this invention.

Other heat sensitive materials can be used in conjunction with donor and receiver sheets to modify their light transmittance. One such material is liquid crystal material which changes reversibly from opaque to translucent as a result of temperature change.

Many other types of materials capable of having their light transmission properties altered can also be employed in the process of this invention such as diazo films capable of forming o'paque colors upon treatment with ammonia. One such process is the Kalvar process which is based upon the use of diazonium compound. In the Kalvar process, a very thin layer, about 0.0005 inches is coated on a film such as a polyester. When a sheet of this material is exposed to ultraviolet light in the range of from about 3,500A to around 4,15OA, the diazonium compound decomposes and liberates nitrogen in the form of tiny bubbles. The gas bubble can then be caused to expand by heating the sheet whereupon tiny vesicles occur in the plastic coating and act as light scattering centers causing the light transmittance of the sheet to change.

Other methods and materials useful to alter the light transmittance of donor or receiver sheets will occur to those skilled in the art.

Particularly preferred materials useful as donor and receiver sheets are those having coatedon one side thereof a transparent conductive coating. Such materials as conductive cellophane, aluminum coated plastic substrates such as aluminized Mylar are particularly preferred since they eliminate the need for the presence of a transparent electrode. ln addition, conduc tively coated transparent materials are preferred because the electric field can be placed across the manifold set without the necessity of including the master to be duplicated within the electric field which is the case when separate electrodes are employed.

As illustrated in F 1G. I, imaging layer 2 contains any suitable electrically photosensitive material 3. Typical organic materials include quinacridones such as: 2,9-

6 dimcthyl quinacridone, 4,]l-dimethyl quinacridonc. 2,10-dichloro-6, l 3-dihydro-quinacridone, 2,9-dimcthoxy-6.l 3-dihydro-quinacridone, 2.4.9,] l-tetrachloro-quinacridone, and solid solutions of quinacridones and other compositions as described in U.S. Pat. No. 3,160,510; carboxamides such as: N-2"-pyridyl- 8, l 3-dioxdinaphtho-(2, l-2,3 )-furan-6-carboxamide, N-2"-( l ",3",5"-dioxodinaphtho-( 2, l -2',3 )-furan6 carboxamide, anthra-( 2,1 )-naphtho-( 2,3-dl-furan- 9, l 4-dione-7-( 2'-methyl-phenyl) carboxamide; carboxanilides such as: 8,l3-dioxodinaphtho-(2,1-2',3')- furan-o-carbox-p-methoxy-anilide, 8,13-dioxodinaphtho-(2, 1-2 ,3) furan-6-carbox-p-methylanilide, 8,13- dioxodinaphtho-(Z, 1-2 ',3' )-furan-6-carbox-mchloranilide, 8,13-dioxodinaphtho-(2,1-2',3 furan-ficarbox-p-cyanoanilide; triazines such as: 2,4-diaminotriazine, 2,4-di l '-anthraquinonyl-amino)-6-( l pyrenyl)-triazine, 2,4-di l anthraquinonyl-aminol-o (l"-naphthyl)-triazine, 2,4-di (l'-naphthyl-amino)-6- (l-perylenyl)-tria2ine, 2,4,6-tri (l',l",l"-pyrenyl)- triazine; benzopyrrocolines such as: 2.3-phthaloyl-7,8- benzopyrrocoline, l-cyano2,3-phthaloyl-7, 8-benzopyrrocoline, l-cyano-2,3-phthaloyl-5-acetamiclo- 7,8-benzopyrrocoline; anthraquinones such as: 1,5-bis- (beta-phenylethyl-amino) anthraquinone, l,S-bis-(3'- methoxypropylamino) anthraquinone, l,5-bis(benzyamino) anthraquinone, 1,5-bis (phenyl-amino) anthraquinone, 1,2,5,6-di-(c,c-diphenyl)-thiazoleanthraquinone, 4-(2'-hydroxyphenylmethoxyaminoJ anthraquinone; azo compounds such as: 2,4,6-tris (N- ethyl-N-hydroxy-ethyl-p-aminophenylazo) ph1oroglu cinol, 1,3,5, 7-tetrahydroxy-2,4,6,8-tetra (N-methyl-N- hydroxyethyl-p-aminophenylazo) naphthalene, 1,3,5- trihydroxy-2,4,6-tris (3 '-nitro-N-methyl-N-hydroxymethyl-4'-aminophenylazo) benzene, 3 methyl-L phenyl-4-( 3 'pyrenylazo )-2-pyrazolin-5-one, 1- (3'pyrenylazo)-2-hydroxy-3-naphthanilide, l-( 3'- pyrenylazo)-2-naphthol, l-( 3 '-pyrenylazo)-2-hydroxy- 3-methy1xanthene, 2,4,6-tris (3-pyrenylazo) phloroglucinol, 2,4,6-tris (1-phenanthrenylazo) phloroglucinol, l-(2'-methoxy-5 '-nitro-phenylazo)-2-hydroxy- 3'-nitro-3-naphthanilide; salts and lakes of compounds derived from 9-phenylxanthene, such as phosphotongstomolybdic lake of 3,6-bis (ethylamino)-9,2'-carboxyphenyl xanthenonium chloride, barium salt of 3-2- toluidine amino-6,2"-methyl-4"-sulphophenylamino- 9,2"'-carboxyphenyl xanthene; phosphomolybdic lake of 3,6-bis (ethylamino)-2,7-dimethyl-9,2'-carbethoxyphenylxanthenonium chloride; diozazines such as: 2,9- dibenzoyl-6, l3-dichloro-triphenodioxazine, 2,9-diacetyl-6,l 3-dichlorotriphenodioxazine, 3,10-dibenzopylamino-2,9-diisopyropoxy-6, l 3-dichloro-triphenodioxazine, 2,9-difuroyl-6,13-dichloro-triphenodioxazine; lakes of fiuorescein dyes, such as: lead lake of 2,7-dinitro-4,5- dibromo fluorescein, lead lake of 2,4,5,7-tetrabromo fluorescein, aluminum lake of 2,4,5,7-tetrabromo- 10,1 1,1 2, l 3-tetrachloro fluorescein; bisazo compositions such as: N,N'-di'[ l-(-naphthy1azo)-2-hydroxy-8-naphthyl] adipdiamide, N,N-dil-(l'-naphthylazo)-2-hydroxy S-naphthyl succinidamide, bis-4, 4'-(2"-hydroxy-8"-N,N'-ditere-phthalamide-l-naphthylazo) biphenyl, 3,3'-methoxy-4,4- diphenyl-bis 1" -azo-2"-hydroxy-3"naphthanilide); pyrenes such as: 1,3,6,8-tetraaminopyrene, l-cyano-6- nitropyrene; phthalocyanines such as: beta-forrn metal free phthalocyanine, copper phthalocyanine, tetrachloro phthalocyanine, the x"-form of metal-freephthalocyanine as described in U.S. Pat. No.

3,357,989; metal salts and lakes of azo dyes. such as: calcium lake of o-bromo-l (l'-sulfo-2-naphthlazo)-2- naphthol. barium salt of Ei-cyano'H l'-sulfo2-naphthylazofZ-naphthol, calcium lake of l-( 2 '-a7.onaphthalene-l '-sulfonic acidl-Z-naphthol, calcium lake of l- (4'-ethyl5 'chloroaZobenzene-2'-sulfonic acid )2- hydroxy-B-naphthoic acid; and mixtures thereof.

Typical inorganic compositions include cadmium sulfide, cadmium sulfoselenide, zinc oxide, zinc sulfide, sulphur selenium, mercuric sulfide, lead oxide, lead sulfide, cadmium selenide, titanium dioxide. indium troix ide and the like.

Other organic materials including organic donoraceeptor (Lewis Acid-Lewis Base) charge transfer com plexes are listed in copending application Ser. No. 708,380 filed Feb. 26. 1968, which is incorporated herein by reference.

In addition to the charge transfer complexes, it is to be noted that many other of the above materials may be further sensitized by the charge transfer complexing technique and that many of these materials may be dyesensitized to narrow, broaden or heighten their spectral response curves.

It is also to be understood that the electrically photosensitive particles themseleves may consist of any suitable one or more of the aforementioned electrically photosensitive materials, either organic or inorganic, dispersed in, in solid solution in, or copolymerized with, any suitable insulating resin whether or not the resin itself is photosensitive. This particular type of particle may be particularly desirable to facilitate dispersion of the particle, to prevent undesirable reactions between the binder and the photosensitive material or between the photosensitive and the activator and for similar purposes. Typical resins of this type include polyethylene, polypropylene, polyamides, polymethacrylates, polyacrylates, polyvinyl chlorides, polyvinyl acetates, polystyrene, polysiloxanes, chlorinated rubbers polyacrylonitrile, epoxies, phenolics, hydrocarbon resins and other natural resins such as rosin derivatives as well as mixtures and copolymers thereof.

The x-form phthalocyanine is preferred because of its excellent photosensitivity although any suitable phthalocyanine may be used to prepare the imaging layer of this invention. The phthalocyanine used may be in any suitable crystal form. It may be substituted or unsubstituted both in the ring and straight chain portions. Reference is made to a book entitled Phthalocyanine Compounds" by F. H. Moser and A. L. Thomas, published by the Reinhold Publishing Company, l963 edition for a detailed description of phthalocyanines and their synthesis.

Referring now to FIG. 2, there is diagramatically shown the process step of exposing to electromagnetic raidation the master to be duplicated in accordance with the process of this invention. In FIG. 2 there is shown manifold set 1, comprising donor sheet 5, imaging layer 2 and receiver sheet 6 resting upon the master to be duplicated 7. The master contains printed area 8 and unprinted area 9. In this case, both donor sheet and receiver sheet 6 contain a thin transparent coating of electrically conductive material such that they function in a dual capacity in the process of this invention. That is, in addition to their function as donor and receiver sheets they also are employed as the electrodes across which a potential is applied from power source 10 through resistor ll. The electrical field can be applied in many ways. Generally, the manifold set is placed between electrodes having different electrical potential. Also, in the case wherein the donor and receiver sheets are electrically insulating, an electrical charge can be imposed upon onr or both of the donor and receiver sheets before or after forming the manifold set by any one of several known methods for inducing a static electrical charge into a material. Static charges can be imposed by contacting the sheet or substrate with an electrically charged electrode. Alternatively. one or both sheets may be charged by using corona discharge devices such as those described in US. Pat. No. 2,588,699 to Carlson. US. Pat. No. 2,777,957 to Walkup, US. Pat. No. 2,885,556 to Gundlach or by using conductive rollers as described in US. Pat. No. 2,980,834 to Tregay et al. or by frictional means as described in US. Pat. No. 2,297,69l to Carlson or other suitable apparatus.

The strength of the electrical field applied across the manifold sandwich depends on the structure of the manifold sandwich and the materials used. For example, if highly insulating receiver and donor substrate materials are used, a much higher field may be applied than if relatively conductive donor and receiver sheets are used. The field strength required may, however, be easily determined. If too large a potential is applied, electrical breakdown of the manifold sandwich will occur allowing arcing between the electrodes. If too little potential is applied, the imaging layer will not transfer in imagewise configuration. By way of example, if a 3 mil Mylar receiver sheet and a 2 mil Mylar donor sheet are used, potentials as high as 20,000 volts may be applied between the electrodes. The preferred field strengths across the manifold sandwich are, however, in the range of from about 2,000 volts per mil to about 7,000 volts per mil of electrically insulating material. Since relatively high potentials are utilized, it is desirable to insert a resistor in the circuit to limit the flow of current. Resistors on the order of from about 1 megohn to about 20,000 mcgohms are conventionally used.

As shown in FIG. 2, electromagnetic radiation 12 passes through donor sheet 5 and strikes imaging layer 2. Some of the radiation passes through imaging layer and receiver sheet 6 to strike the master to be duplicated 7. In the non-image areas 9 of master 7, a large amount of the electromagnetic radiation striking the master is reflected back through receiver sheet 6 to imaging layer 2, thus exposing those portions of the imaging layer from the opposite direction from the light source. In the image areas 8 of master 7, the electromagnetic radiation is absorbed and very little or none is reflected back to imaging layer 2, thus leaving those areas of imaging layer 2 exposed from only one side. Surprisingly, only a small amount of radiation from the opposite direction is needed to provide differential radiation and imagewise fracture of the imaging layer. The amount of light which most manifold imaging layers transmit is about 10% of that required to be aetinic to the layer under normal imaging conditions. Only about %75% of this transmitted light need be reflected back from the unprinted portion of the master to be duplicated in order to provide imagewise fracture of the imaging layer. The actual amount of light required varies depending upon the sensitivity of the electrically photosensitive material in the imaging layer and, of course, the opacity of the binder, donor, receiver and electrodes when present.

A visible light source, an ultraviolet light source or any other suitable source of electromagnetic radiation may be used to expose the imaging layer of this invention. The electrically photosensitive material is chosen so as to be responsive to the wavelength of the electromagnetic radiation used. It is to be noted that different electrically photosensitive material have different spectral responses and that the spectral response of many electrically photosensitive materials may be modified by dye sensitization so as to either increase or narrow the spectral response of a material to a peak or to broaden it to make it more panchromatic in its re sponse. In addition. the electromagnetic radiation is chosen so as to be reflected by the unprinted surface or white space of the master to be duplicated. The amount of exposure is usually dependent upon the sensitivity of the electrically photosensitive material employed in the imaging layer. For most materials, exposure in the order of from ten to several thousand foot-candle seconds is sufficient. Normally 20 to 50 foot-candle seconds will provide satisfactory results but for some imaging layers such as the black colored layers, up to about 2.500 foot-candle seconds are employed.

Referring now to FIG. 3, there is diagramatically shown the step of separating the manifold set after exposure to electromagnetic radiation. In FIG. 3 donor sheet 5 is shown being separated from receiver sheet 6 which is residing upon the master 7. During the separation step. an electric field is being supplied from power source 10 through resistor 11. Portions of imaging layer 2, which were directly over image areas of master 7 are found to be adhering to receiver sheet 6 while portions of imaging layer 2 over non-image areas of master 7 and thus exposed to electromagnetic radiation from both directions are retained on donor sheet 5. Thus, upon separation of the donor and receiver sheets, a positive corresponding to the image on master 7 is found on receiver sheet 6 while a negative of the master image is found on donor sheet 5.

As indicated in FIG. 3 above, imaging layer 2 transfers to the receiver sheet 5 in the areas corresponding to the image areas of master 7. This is due to the fact that imaging layer 2 is releasably residing on donor sheet 5. For ease of handling and storage of the donor sheets. it is a common practice to employ a temporarily unfracturable imaging layer 2 on donor sheet 5 and when ready to be employed in the imaging process of this invention the imaging layer is rendered structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation. The process of rendering the imaging layer structurally fracturable is termed activation. The activation step may take many forms, such as heating the imaging layer or applying a substance to the surface of the imaging layer or including a substance in the imaging layer which substance upon proper treatment renders the imaging layer releasable. The substance so employed is termed an activator. Preferably the activator should have a high resistivity so as to prevent electrical breakdown of the manifold set. Accordingly, it will be generally found to be desirable to purify commercial grades of activators so as to remove impurities which might impart a higher lever of conductivity. This may be accomplished by running the fluids through a clay column or by employing any other suitable purification technique. Generally speaking the activator may consist of any suitable material having the aforementioned properties. For purposes of this specification and the appended claims. the term activator shall be understood to include not only materials which are conven- 1O tionally termed solvents but also those which are partial solvents. swelling agents or softening agents for the iniaging layer. The activator can be applied at any point in the process prior to separation of the manifold sandwich.

It is generally preferable that the activator have a relatively low boiling point so that fixing of the resulting image can be accomplished upon evaporation of the activator. If desired. fixing of the image can be accomplished more quickly with mild heating at most. It is to be understood. however, that the invention is not limited to the use of these relatively volatile activators. In fact. very high boiling point non-volatile activators including silicone oils such as dimethyl-polysiloxanes and very high boiling point long chain aliphatic hydrocarbon oils ordinarily used as transformer oils such as Wemco-C transformer oil, available from Westinghouse Electric Co., have also been successfully utilized in the imaging process. Although these less volatile activators do not dry off by evaporation. image fixing can be accomplished contacting the final image with an absorbent sheet such as paper which absorbs the activator fluid. In short. any suitable volatile or non-volatile activator may be employed. Typical activators include Sohio Odorless Solvent 3440, an aliphatic (kerosene) hydrocarbon fraction, available from Standard Oil Co. of Ohio, carbon tetrachloride, petroleum ether, Freon 214 (tetrafluorotetrachloropropane), other halogenated hydrocarbons such as chloroform. methylene chloride, trichloroethylene, perchloroethylene, chlorobenzene, trichloromonofluoroethane, trichlorotrifluoroethane, ethers such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran. ethyleneglycol monoethyl ehter, aromatic and aliphatic hydrocarbons such as benzene, toluene, xylene, hexane, cyclohexane, gasoline, mineral spirits and white mineral oil. vegetable oils such as coconut oil. babussu oil, decane. dodecane and mixtures thereof. Sohio Odorless Solvent 3440 is preferred because it is odorless, non-toxic and has a relatively high flash point.

In a particularly preferred method of imaging in accordance with the process of this invention, a rolling optical system is employed, which performs the double function of subjecting the manifold set to an electric field while exposing the master to electromagnetic radiation. Basically, the rolling optical system is either held stationary while the manifold set is passed tangentally in contact therewith or the optical system is rolled across a stationary manifold set. Preferably, the rolling optical system is rotatably mounted in a fixed position while the manifold set is passed under the cylinder and in contact therewith. Referring now to FIG. 4, there is diagramatically shown such a rolling optical system. In FIG. 4 there is generally shown cylinder 17 comprising transparent base 201 having disposed therein a tubular source of electromagnetic radiation such as a filament lamp or fluorescent bulb 203. In the preferred embodiment of this invention, a reflective shield 205 is provided around electromagnetic radiation source 203 to direct the radiation toward one segment of cylinder 201. Transparent cylinder 20] can comprise any suitable material which is transparent to the electromagnetic radiation employed. Thus, most commonly the transparent cylinder is glass and the electromagnetic radiation is in the visible light range. Other transparent materials can be employed keeping in mind the electromagnetic radiation employed. Plastic material such as polymethyl methacrylate sold under the trade names Plcxiglass and Lucite by Rohm 8; Haas Co. and E. l. du- Pont de Nemours 8; Co, Inc. can be employed. On the circumference of transparent cylinder there is coated a layer of electrically conductive material 207. The conductive coatings can comprise any electrically conductive material which is transparent to the electromagnetic radiation employed. Thus, metals such as alu minum. gold. silver, copper, magnesium and other metals can be deposited on the cylinder in thin coatings to provide the conductive layer while allowing electromagnetic radiation to pass through. In a preferred embodiment of this invention, a tin oxide coated glass cylinder is employed.

The conductive coating 207 around the cylinder can be provided by either coating a thin conductive film directly on the outside of the cylinder or a conductive coating on a transparent film substrate can be employed as a covering over the cylinder with the conductive coating pressing against the outer surface of the cylinder. For example. a conductive coating such as aluminum coated on transparent flexible polyethylene terephthalate film can be wrapped tightly around a transparent cylinder to provide an insulated conductive coating on the cylinder.

The thickness of the conductive coating 207 can vary greatly. Normally the thickness of the conductive coating is in the range of from about 0.001 micron to about 0.1 micron. Of course, other thicknesses can be employed if suitable.

Conductive coating 207 is covered with an insulating film 209 which serves to provide an electrical barrier between the conductive coating and the materials which come in contact with the cylinder. Such insulating films are preferably high dielectric strength polymeric materials. Typical insulating materials include polyethylene, polyporpylene, polyester, polyethylene terephthalate, polystyrene, cellulose acetate and polystyrene. Other electrically insulating materials possessing the required transparency to electromagnetic radiation will occur to those skilled in the art. Mylar is preferred because of its durability and its excellent insulative qualities. Mylar having a transparent conductive evaporated metal coating on one side is particularly preferred because when wrapped around a glass cylinder it provides both the conductive and insulating coating around the cylinder.

in a particularly preferred embodiment of this invention, there is provided within the transparent cylinder 201 an electrical power supply 211 which can be employed to provide a high dc. voltage to the conductive layer. This power supply can then be grounded through conventional concentric bearings on one end of the cylinder which ground can be placed in communication with a second electrode so as to provide an appropriate electric field depending upon the imaging system in which the apparatus is employed. Alternatively, an external power supply can be employed by providing an electrical connection between the conductive coating and a sliding or rolling contact placed within the concentric bearing of the cylinder.

Also shown in FIG. 4 is manifold set generally indicated as 11 comprising receiver sheet 215, imaging layer 217 and donor sheet 219. Donor sheet 219 is provided with a conductive backing 220. Conductive coating 220 can be any transparent coating such as cellophane or a vacuum deposited metal of a thickness so as to be at least about 80% transparent to the electromagnetic radiation employed. Below manifold set 1 1, there is placed an original document 22] in optical reflex contact with manifold sandwich 11. Alternatively. original document 22] can rest upon a base 223 which is connected to a common ground with power supply 221 providing an electric field acrossmanifold set 11. By connecting the conductive surface 220 to a common ground with power supply 2] 1, an electric field can be established across the manifold set without including the original document. This later arrangement is a preferred embodiment of this invention because the original document is not included within the electric field, thus eliminating a variable in the imaging process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples further specifically illustrate the present invention. The examples below are intended to illustrate various preferred emboidments of the improved imaging method. The parts and percentages are by weight unless otherwise indicated.

EXAMPLE I A commercial metal-free phthalocyanine is first purified by o-dichlorobenzene extraction to remove organic impurities. Since this extraction step yields the less sensitive beta crystalline form, the desired x-form is in accordance with the procedure of Example I of US. Pat. No. 3,357,989. The xform phthalocyanine thus produced is used to prepare the imaging layer according to the following procedure: About 5 grams of the x x-form phthalocyanine is added to about 5 grams of Algol Yellow GC, l,2,5,6-(C,C'-diphenyl) thiazoleanthraquinone. C. I. No. 67300, available from General Dyestuffs, and about 2.8 grams of purified Watchung Red B, l-(4'-methyl-5-chlorobenzene-2'-sulfonic acid)-2-hydroxy-3-naphthoic acid, C. I. No. 15865, available from E. l. duPont de Nemours & Co., which is purified as follows: approximately 240 grams of the Watchung Red B is slurried in about 2400 milliliters of Sohio Odorless Solvent 3440. a mixture of kerosene fractions available from the Standard Oil Company of Ohio. The slurry is then heated to a temperature of about 65 C. and held there for about one-half hour. The slurry is then filtered through a glass sintered filter. The solids are then reslurried with petroleum ether to C.) available from Matheson, Coleman and Bell Division of the Matheson Company, East Rutherford, NJ. and filtered through a glass sintered filter. The solids are then dried in an oven at about 50C.

About 8 grams of Sunoco Microcrystalline Wax Grade 5825 having an ASTM-D-l27 melting point of 15 lF. and about 2 grams of Paraflint R. G., a low molecular weight paraffinic material. available from the Moore & Munger Company, New York City, about 144 milliliters of petroleum ether (90 to 120C.) and about 40 milliliters of Sohio Odorless Solvent 3440 are placed with the pigments in a glass jar containing onehalf inch flint pebbles. The mixture is then milled by revolving the glass jar at about 70 rpm. for about lo hours. The mixture is then heated for approximately 2 hours at about 45C. and allowed to cool to room temperature. The mixture is then ready for coating on the donor substrate. The paste-like mixture is then coated in subdued green light on 2 mil Mylar (a polyester formed by the condensation reaction between ethylene glycol and tetrephthalic acid available from E. lv du- Pont de Nemours & Co., Inc.) with a No. 36 wire wound drawdown rod to produce a coating thickness when dried of approximately 7 /2 microns. The coating and two mil Mylar sheet is then dried in the dark at a temperature of about 33C. for one-half hour. The coating is activated by applying thereto Sohio Odorless Solvent 3440 by means of a soft brush and a 2 mil thick Mylar receiver sheet is laid over the activated imaging layer.

The thus formed manifold sandwich is then placed donor side down on the tin oxide surface of a NESA glass electrode. A master to be duplicated is laid over the receiver sheet and a black paper electrode is laid over the master connected to the positive terminal of a 9,000 volt dc. power supply. The negative terminal of the power supply is connected to the NESA coating in series with a 5,500 megohm resistor. With the voltage applied. a white incandescent uniformly distributed light is projected upward through the NESA glass and the donor sheet providing a total incident energy of about 2l00 foot-candle seconds on the donor side of the imaging layer. After exposure the black paper electrode together with the master and receiver are removed from the donor and a positive right-reading transparency is observed on the receiver. A negative wrong-reading image resides on the donor sheet.

EXAMPLE The procedure of Example I is repeated except that prior to placing the master on the receiver the imaging layer is exposed to general illumination while under a field of 9,000 volts for a total incident energy of 504 foot-candle seconds. During this exposure the NESA is connected to the positive terminal of the power source and the paper electrode is connected to the negative terminal. The electric field is discontinued while a master is again placed over the receiver and the paper electrode placed over the master. With the field reapplied but with the same polarity as in Example I, the master is exposed through the NESA and manifold set for a total incident energy of 1470 foot-candle seconds. Upon separation of the manifold set while under the electric field, a wrong-reading negative image is observed on the donor while a right-reading positive image resides on the receiver sheet.

EXAMPLE Ill An imaging layer comprising electrically photosensitive materials dispersed in a binder is first prepared. About 100 parts of Naphthol Red B, code -7575 available from American Cyanamide Company is dissolved in reagent grade ethylenediamine. The solution is filtered immediately through course filter paper and the filtrate mixed with an equal volume of reagent grade isopropanol. The Naphthol Red B precipitates in the alcohol and is removed by means of a centrifuge. After separating the ethylenediamine and alcohol, the electrically photosensitive material is washed and filtered with successive amounts of isopropanol, a 2:1 volume mixture of isopropanol and deionized water and five washings with deionized water until the filtrate is neutral. Finally, the material is washed with dimethylformamide and methanol in succession until the filtrates have a pale yellow color. The Naphthol Red B is then dried at 40C. under vacuum. About 3 parts of the purified Naphthol Red B is combined with about 60 parts of clay purified petroleum ether and ball milled for 48 hours.

A binder material is prepared by combining about l.5 parts of Paraflint R6, at low molecular weight paraffinic material available from the Moore and Munger Co., New York City; about 3 parts of Polyethylene DYLT available from Union Carbide Corporation; about 0.5 parts of a vinyl acetate-ethylene copolymer available as Elvax 420 from E. l. duPont de Nemours Inc. and about 2.5 parts of a modified polystyrene available as Piccotex from Pennsylvania Industrial Chemical Co. with about 15 parts of Sohio Odorless Solvent 3440. The mixture is heated until dissolved and then cooled. The binder and pigment mixtures are then ball milled together for a period of about 16 hours. After milling the mixture is heated to 65C for 2 hours and then about 45 parts of isopropyl alcohol is added to the mixture and the mixture is milled in the ball mill for 20 minutes. The resulting imaging material is then coated on 3 mil Mylar with a doctor knife set at a gap of 4.4 mil to produce a donor. The donor is dried at a temperature of about 1 l5F.

The donor is then placed on the tin oxide surface of a NESA glass plate with the imaging layer facing away from the tin oxide. The imaging layer is activated by applying Sohio Odorless Solvent 3440 by means of a brush and a sandwich is formed by placing a transparent film of polypropylene over the activated donor as a receiver. A master is placed over the receiver and a black paper electrode is placed over the master and connected to the positive terminal of an 8,500 volt DC. power supply. The NESA is connected to the negative terminal of the power supply and while the manifold set is subjected to the electric field the master is exposed by radiating light from a white incandescent light source through the NESA and manifold set. The total incident energy at the donor side of the imaging layer is 42 foot-candle seconds. Upon separation of the manifold set while under a field, a positive right-reading image is observed on the receiver while a negative wrong-reading image is observed on the donor sheet.

EXAMPLE [V The procedure of Example III is repeated with the exception that the master to be duplicated is placed upon the tin oxide surface of the NESA glass and the manifold set, donor side down, is placed over the master. The imaging layer is activated by applying thereto a film of Sohio Odorless Solvent 3440 after which a sheet of polypropylene is placed over the activated imaging layer. A sheet of electrically conductive, transparent cellophane is placed over the polypropylene film as the second electrode and with the field applied the master is exposed through the transparent cellophane electrode and the manifold set with a total incident energy at the receiver side of the imaging layer of 27 foot-candle seconds from a white incandescent light source. Upon separation of the manifold set with the field applied, a negative wrong-reading image is observed on the polypropylene receiver sheet and a positive mirror image is observed on the donor sheet.

EXAMPLE V The procedure of Example I is repeated with the exception that prior to separating the manifold set the polarity of the electric field is reversed. Upon separation of the manifold set, there is observed a positive but wrong-reading image on the donor sheet. The receiver sheet is then discarded and a sheet of polyethylene coated paper wetted with Sohio Odorless Solvent 3440 is placed over the image on the donor sheet, which is resting on the NESA electrode. The black paper electrode is placed over the polyethylene coated paper and the electric field is established with the same voltage and polarity as employed during the exposure step of Example I. With this electric field applied. the polyethylene coated paper is separated from the donor sheet. A positive right-reading image is obsen ed on the polyethylene coated paper. which image formerly resided on the donor sheet.

EXAMPLE VI The procedure of Example II is repeated with the exception that a clear transparent smooth film of a copolymer of styrene and acrylonitrile (Polyflex 200 copolymer film). soluble in acetone. partly soluble in toluene and insoluble in heptane. coated with a penetrant and treated as disclosed in Example lll of US. Pat. No. 3.l 11.584 is employed as the receiver. The film is placed over the imaging layer with its coated side facing away from the layer. After separation the coated surface of the receiver sheet which is the opposite that bearing the image is uniformly subjected to brief. intense irradiation of the type employed in the thermographic copying process described in US. Pat. No. 189L165 incorporated herein by reference. Upon exposure to the irradiation. the receiver becomes lightdiffusing over its entire surface thus producing a blackon-white positive copy of the master.

Other modifications and ramifications of the present invention will occur to those skilled in the art upon a reading of the present disclosure. These are intended to be included within the scope of the invention.

What is claimed is:

l. A contact reflex imaging process comprising the steps of:

a. providing a manifold set comprising an electrically photosensitive imaging layer. structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which said layer is sensitive, sandwiched between a donor sheet and a receiver sheet. said donor and receiver sheets being at least partially transparent to said radiation;

b. contacting one side of said manifold set with a master to be duplicated;

c. applying an electric field across said imaging layer;

d. exposing said master to electromagnetic radiation to which said layer is sensitive through said manifold set said exposure being at least sufficient to provide uniform transfer of said imaging layer in the absence of said master; and

e. separating said set while under said field.

2. The method of claim 1 wherein the imaging layer is rendered structurally fracturable by the application thereto of an activator.

3. The method of claim 1 wherein the master contacts the receiver side of the manifold set.

4. The process of claim 1 wherein the master contacts the donor side of the manifold set.

S. The method of claim 1 wherein the imaging layer comprises an electrically photosensitive imaging material dispersed in a binder.

6. The method of claim 5 wherein the electrically photosensitive material is an organic material.

7. The method of claim 6 wherein the organic material is metal-free phthalocyanine.

8. The method of claim 1 wherein the light transmittance of at least one of the donor and receiver sheets is alter-able.

9. The method of claim 8 wherein the light transmittance of at least one of the donor and receiver sheets is altered after the separation of said set.

10. The method of claim I wherein the electromagnetic radiation is in the visible light range.

11. The method of claim 1 wherein the electric field is in the range of from about 2.000 volts to about 7.000 volts per mil.

12. A contact reflex imaging process comprising the steps of.

a. providing a manifold set comprising an electrically photosensitive imaging layer. structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which said layer is sensitive, sand wiched between a donor sheet and a receiver sheet, said donor and receiver sheets being at least partially transparent to said radiation;

b. contacting one side of said manifold set with a master to be duplicated;

c. applying a first electric field across said imaging layer;

d. exposing said master to electromagnetic radiation to which said imaging layer is sensitive through said manifold set said exposure being at least sufficient to provide uniform transfer of said imaging layer in the absence of said master.

e. altering said electric field across said imaging layer wherein said alteration is selected from the group consisting of reversing. grounding and reducing the potential across said set;

f. separating said manifold set while under said altered electric field to provide a positive image on one of said donor and receiver sheets and a negative image on the other and whereby the location of said images with respect to said donor and receiver sheets are reversed from that obtained in the above process in the absence of step (d).

13. The method of claim 12 further including the steps of:

a. contacting at least one of the images with a substrate wetted with an activator for said imaging layer;

b. applying an electric field across said imaging layer having the same polarity as said first electric field;

c. separating said substrate while under said electric field from the sheet originally bearing said image thereby transferring said image to said substrate.

14. The process of claim 12 wherein the alteration of said field is a reversal of the potential across said set.

15. The process of claim 12 wherein the alteration of said electric field is a grounding of the potential across said set.

16. The process of claim 12 wherein the alteration of said electric field is a reduction of said electric field to an amount less than one third of the original electric field.

17. The process of claim l2 wherein the electrically photosensitive material is an organic material.

18. The process of claim 19 wherein electrically photosensitive material comprises metal-free phthalocyanine.

19. The process of claim 12 wherein the first electric field is in the range of from about 2,000 volts to about 7.000 volts per mil.

20. The process of claim 12 wherein the master contacts the donor side of said manifold setv 21. The process of claim 12 wherein the master contacts the receiver side of said manifold set.

22. The process of claim 12 wherein the electrically photosensitive material is dispersed in a binder.

23. The process of claim l2 wherein the light transmittance of at least one of the donor and receiver sheets is alterable.

24. The process of claim 23 wherein the light transmittance of at least one of the donor and receiver sheets is altered.

25. A contact reflex imaging process comprising the steps of;

a. providing a manifold set comprising an electrically photosensitive imaging layer. structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which said layer is sensitive, sandwiched between a donor and a receiver sheet, said donor and receiver sheets being at least partially transparent to said radiation;

b. applying an electric field across said imaging layer;

c. uniformly exposing said imaging layer to electromagnetic radiation to which said layer is sensitive;

d. contacting one side of said manifold set with a master to be duplicated;

e. exposing said master to electromagnetic radiation to which said layer is sensitive through said manicontacts the donor side of said manifold set.

27. The process of claim 25 wherein the master contacts the receiver side of said manifold set.

28. The process of claim 25 wherein the electrically photosensitive material is an organic material.

29. The process of claim 28 wherein the electrically photosensitive material comprises metal-free phthalocyanine.

30. The process of claim 25 wherein the electric field is in the range of from about 2,000 volts to about 7,000 volts per mil.

3]. The process of claim 25 wherein the electrically photosensitive material is dispersed in a binder.

32. The process of claim 25 wherein the light transmittance of at least one of the donor and receiver sheets is alterable.

33. The process of claim 32 wherein the light transmittance of at least one of the donor and receiver sheets is altered. 

1. A CONTACT REFLEX IMAGING PROCESS COMPRISING THE STEPS OF: A. PROVIDING A MANIFOLD SET COMPRISING AN ELECTRICALLY PHOTOSENSITIVE IMAGING LAYER, STRUCTURALLY FRACTURABLE IN RESPONSE TO THE COMBINED EFFECT OF AN APPLIED ELECTRIC FIELD AND EXPOSURE TO ELECTROMAGNETIC RADIATION TO WHICH SAID LAYER IS SENSITIVE, SANDWICHED BETWEEN A DONOR SHEET AND A RECEIVER SHEET, SAID DONOR AND RECEIVER SHEETS BEING AT LEAST PARTIALLY TRANSPARENT TO SAID RADIATION, B. CONTACTING ONE SIDE OF SAID MANIFOLD SET WITH A MASTER TO BE DUPLICATED, C. APPLYING AN ELECTRIC FIELD ACROSS SAID IMAGING LAYER, D. EXPOSING SAID MASTER TO ELECTROMAGNETIC RADIATION TO WHICH SAID LAYER IS SENSITIVE THROUGH SAID MANIFOLD SET SAID EXPOSURE BEING AT LEAST SUFFICIENT TO PROVIDE UNIFORM TRANSFER OF SAID IMAGING LAYER IN THE ABSENCE OF SAID MASTER, AND E. SEPARATING SAID SET WHILE UNDER SAID FIELD.
 2. The method of claim 1 wherein the imaging layer is rendered structurally fracturable by the application thereto of an activator.
 3. The method of claim 1 wherein the master contacts the receiver side of the manifold set.
 4. The process of claim 1 wherein the master contacts the donor side of the manifold set.
 5. The method of claim 1 wherein the imaging layer comprises an electrically photosensitive imaging material dispersed in a binder.
 6. The method of claim 5 wherein the electrically photosensitive material is an organic material.
 7. The method of claim 6 wherein the organic material is metal-free phthalocyanine.
 8. The method of claim 1 wherein the light transmittance of at least one of the donor and receiver sheets is alterable.
 9. The method of claim 8 wherein the light transmittance of at least one of the donor and receiver sheets is altered after the separation of said set.
 10. The method of claim 1 wherein the electromagnetic radiation is in the visible light range.
 11. The method of claim 1 wherein the electric field is in the range of from about 2,000 volts to about 7,000 volts per mil.
 12. A contact reflex imaging process comprising the steps of: a. providing a manifold set comprising an electrically photosensitive imaging layer, structurally fracturable in response to the combined effect of an applied electric field and exposure to electromagnetic radiation to which said layer is sensitive, sandwiched between a donor sheet and a receiver sheet, said donor and receiver sheets being at least partially transparent to said radiation; b. contacting one side of said manifold set with a master to be duplicated; c. applying a first electric field across said imaging layer; d. exposing said master to electromagnetic radiation to which said imaging layer is sensitive through said manifold set said exposure being at least sufficient to provide uniform transfer of said imaging layer in the absence of said master; e. altering said electric field across said imaging layer wherein said alteration is selected from the group consisting of reversing, grounding and reducing the potential across said set; f. separating said manifold set while under said altered electric field to provide a positive image on one of said donor and receiver sheets and a negative image on the other and whereby the location of said images with respect to said donor and receiver sheets are reversed from that obtained in the above process in the absence of step (d).
 13. The method of claim 12 further including the steps of: a. contacting at least one of the images with a substrate wetted with an activator for said imaging layer; b. applying an electric field across said imaging layer having the same polarity as said first electric field; c. separating said substrate while under said electric field from the sheet originally bearing said image thereby transferring said image to said substrate.
 14. The process of claim 12 wherein the alteration of said field is a reversal of the potential across said set.
 15. The process of claim 12 wherein the alteration of said electric field is a grounding of the potential across said set.
 16. The process of claim 12 wherein the alteration of said electric field is a reduction of said electric field to an amount less than one third of the original electric field.
 17. The process of claim 12 wherein the electrically photosensitive material is an organic material.
 18. The process of claim 19 wherein electrically photosensitive material comprises metal-free phthalocyanine.
 19. The process of claim 12 wherein the first electric field is in the range of from about 2,000 volts to about 7,000 volts per mil.
 20. The process of claim 12 wherein the master contacts the donor side of said manifold set.
 21. The process of claim 12 wherein the master contacts the receiver side of said manifold set.
 22. The process of claim 12 wherein the electrically photosensitive material is dispersed in a binder.
 23. The process of claim 12 wherein the light transmittance of at least one of the donor and receiver sheets is alterable.
 24. The process of claim 23 wherein the light transmittance of at least one of the donor and receiver sheets is altered.
 25. A contact reflex imaging process comprising the steps of: a. providing a manifold set comprising an electrically photosensitive imaging layer, structurally fracturable in response to the combined effect of an applieD electric field and exposure to electromagnetic radiation to which said layer is sensitive, sandwiched between a donor and a receiver sheet, said donor and receiver sheets being at least partially transparent to said radiation; b. applying an electric field across said imaging layer; c. uniformly exposing said imaging layer to electromagnetic radiation to which said layer is sensitive; d. contacting one side of said manifold set with a master to be duplicated; e. exposing said master to electromagnetic radiation to which said layer is sensitive through said manifold set while said manifold set is subjected to an electric field said exposure being at least sufficient to provide uniform transfer of said imaging layer in the absence of said master; and f. separating said set while under said field.
 26. The process of claim 25 wherein the master contacts the donor side of said manifold set.
 27. The process of claim 25 wherein the master contacts the receiver side of said manifold set.
 28. The process of claim 25 wherein the electrically photosensitive material is an organic material.
 29. The process of claim 28 wherein the electrically photosensitive material comprises metal-free phthalocyanine.
 30. The process of claim 25 wherein the electric field is in the range of from about 2,000 volts to about 7,000 volts per mil.
 31. The process of claim 25 wherein the electrically photosensitive material is dispersed in a binder.
 32. The process of claim 25 wherein the light transmittance of at least one of the donor and receiver sheets is alterable.
 33. The process of claim 32 wherein the light transmittance of at least one of the donor and receiver sheets is altered. 